Internal combustion engine

ABSTRACT

A metallic panel for an internal combustion engine, the panel being of the kind not supporting a load. The panel is divided into a peripheral portion and a central portion the two portions being interconnected by at least one strip of metal and the spaces defined between the edges of the portions being occupied by a filling which is formed from a flexible non-metallic material. The two portions are substantially isolated from each other and the radiation of noise from the central portion is substantially reduced.

United States Patent 1 91 111 3,726,365 Russell 5] Apr. 1111, 1973 [5 INTERNAL COMBUSTION ENGINE 2,721,028 10/1955 Dills ..188/1BUX [76] Inventor: Michael Frederick Russell, 67 $332 51322 Swakeleys Dnve, Mlddlesex 3,078,971 2/1963 Wallerstein gland 3,160,549 12/1964 Caldwell @131... [22] Filed, Feb 5 1971 3,388,772 6/1968 Marsh et a1. ..l88/1 B [21] Appl. No.: 112,868 Primary Examiner-Duane A. Reger Attorney-Holman & Stern [30] Foreign Application Pnonty Data 57] ABSTRACT Feb. 25, 1970 Great Bntain ..8,985/70 A metallic panel for an i l mbustion engine, the panel being of the kind not supporting a load. The 12%] Cell ..188/1 B, 35 panel is divided into a peripheral portion and a central d B 198 portion the two portions being interconnected by at 1 le 0 188/] least one strip of metal and the spaces defined between the edgesof the portions being occupied by a 56 R} d filling which is formed from a flexible non-metallic 1 e erences material. The two portions are substantially isolated UNITED STATES PATENTS from each other and the radiation of noise from the central portion is substantially reduced. 1,637,864 8/1927 Kolster ..188/1 B X 2,541,159 2/1951 Geiger ..'l88/l B X 3 Claims, 1 Drawing Figure PAIENTED 3,726,365

- I INVENTOR ATTORNEYS INTERNAL COMBUSTION ENGINE This invention relates to internal combustion engines and more particularly to an exterior metal panel of such an engine which is substantially load free.

There can be many such panels on an internal combustion engine. For instance, the timing gear cover, the sump, the valve gear cover and in some instances the side walls of the crankcase. Such panels can be set into vibration by the forces generated within the engine when it is in operation and this vibration can radiate objectionable noise.

The object of the invention is to provide for damping and isolation of the panel to reduce noise emission.

According to the invention a panel of the kind specified is divided into a central portion and a peripheral portion, the latter being adapted to be secured to the engine, the two portions being connected by at least one strip of metal, the gap or gaps between the adjacent edges of said portions being filled by a flexible visco-elastic material which is bonded to said edges thereby to damp relative motion between said portions.

One example of'a panel of an internal combustion engine in accordance with the invention is shown in the accompanying drawing wherein is shown the timing cover of a compression ignition engine. The cover is of cast construction and is formed from light alloy. The cover includes a central portion and a flanged peripheral portion 11. The peripheral portion is provided with apertures for the reception of retaining bolts whereby the cover can be secured to the engine.

The central portion 10 and the peripheral portion 11 are interconnected by three strips 12 of metal formed during the casting operation and these strips act to locate the two portions relative to each other and add strength to the cover. Furthermore, the strips 12 are of a considerable length so that they can flex to permit relative movement between the portions. The gaps between the portions are filled with a filling 13 formed from a flexible visco-elastic material such as rubber which is bonded or otherwise secured to the adjacent edges of the portions. The rubber acts to damp the relative movement of the portions by viscous and hysteritic loss. The rubber is deformed in shear by the relative movement of the portions.

In most cases the resonant frequency of the center portion can be arranged to lie below the frequency at which it becomes an effective radiator of sound. It is essential to ensure that the central portion has an un-symmetrical form and furthermore, that it is generally devoid of thick ribs and thin sections (i.e. over twice and under half the average thickness'respectively) unless the ribs are specifically designed to increase the motion at the edges of the central portion compared with the motion elsewhere in the central portion.

Having thus described my invention'what I claim as new and desire to secure by Letters Patent is:

l. A metal cover panel for an internal combustion engine, the panel being substantially load free, the panel being divided into a central portion and a peripheral portion, the latter being adapted to be secured to the main body of the engine, at least one strip of metal interconnecting the two portions of the panel, a flexible visco-elastic filler material filling the gap or gaps between the adjacent edges of said portions, said filler material being bonded to said edges thereby to damp relative motion between said portions. 2. A metal panel as claimed in claim 1 in which the central portion is of unsymmetrical form.

3. A metal panel as claimed in claim 2 in which the central portion is generally devoid of thick ribs and thin sections unless the ribs are specifically designed to increase the motion at the edges of the central portion as compared with the motion elsewhere in the central portion. I 

1. A metal cover panel for an internal combustion engine, the panel being substantially load free, the panel being divided into a central portion and a peripheral portion, the latter being adapted to be secured to the main body of the engine, at least one strip of metal interconnecting the two portions of the panel, a flexible visco-elastic filler material filling the gap or gaps between the adjacent edges of said portions, said filler material being bonded to said edges thereby to damp relative motion between said portions.
 2. A metal panel as claimed in claim 1 in which the central portion is of unsymmetrical form.
 3. A metal panel as claimed in claim 2 in which the central portion is generally devoid of thick ribs and thin sections unless the ribs are specifically designed to increase the motion at the edges of the central portion as compared with the motion elsewhere in the central portion. 